Embodiments of the inventive concepts are directed to semiconductor devices and methods for fabricating the same, and more particularly, to semiconductor devices that include field effect transistors and methods for fabricating the same.
Semiconductor devices include integrated circuits that include metal-oxide-semiconductor field effect transistors (MOSFETs). As sizes and design rules of semiconductor devices have been reduced, MOSFETs have been scaled down. Operating characteristics of semiconductor devices may deteriorate by the size reduction of the MOSFETs.
A semiconductor device may have a cell region and a peripheral region around the cell region, and a shallow-trench isolation (STI) layer of a cell region and a STI layer of a peripheral circuit region may each include a liner nitride layer. A liner nitride layer of the STI layer of the peripheral circuit region can function as an electron trap layer when a transistor is formed thereon. Thus, an effective channel length of the transistor is reduced. In addition, the STI layers of the cell region and the peripheral circuit region may be recessed from top surfaces of active regions. When the STI layer is recessed from the top surface of the active region, a gate electrode layer on the STI layer may not be completely etched during a gate patterning process. In this case, a portion of the gate electrode layer remains on the STI layer, which can cause an electrical short between adjacent gate electrodes.